NtFlushWriteBuffer - NtDoc

Native API online documentation, based on the System Informer (formerly Process Hacker) phnt headers 
#ifndef _NTMMAPI_H
// Misc.
#if (PHNT_MODE != PHNT_MODE_KERNEL)

NTSYSCALLAPI
NTSTATUS
NTAPI
NtFlushWriteBuffer(
    VOID
    );

#endif
#endif

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#ifndef _NTZWAPI_H

NTSYSCALLAPI
NTSTATUS
NTAPI
ZwFlushWriteBuffer(
    VOID
    );

#endif

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Function NtFlushWriteBuffer does nothing...

It test IRQ Level, and call HAL export named KeFlushWriteBuffer.

KeFlushWriteBuffer as first asm code has ret, so it returns immediately.

Next NtFlushWriteBuffer clear eax (set result of call to STATUS_SUCCESS) and returns to User-Mode.

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